Preparation method of trivalent chromium black passivator

A passivation agent, trivalent chromium technology, applied in the direction of metal material coating technology, can solve the problems of hexavalent chromium toxicity and application limitations, and achieve the effect of low price, stable performance and good performance.

Inactive Publication Date: 2014-03-26
TIANJIN DAGANG GALVANIZED FACTORY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, hexavalent chromium is toxic, and its application is gradually limited

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0007] The formula is: 18g / L of chromium chloride, 3g / L of chromium nitrate, 4g / L of cobalt nitrate, 10g / L of sodium dihydrogen phosphate, 15g / L of malonic acid, 3g / L of nickel sulfate and It is made of ionized water, the operating temperature is 40°C, the pH value is controlled at 3.0, and the passivation time is 80 seconds. The surface color of the metal zinc layer is bright black, and there is a uniform passivation film on the surface. The test result of the neutral salt spray test 96H is 9 grades.

Embodiment 2

[0009] The formula is: 25g / L of chromium chloride, 5g / L of chromium nitrate, 4g / L of cobalt nitrate, 15g / L of sodium dihydrogen phosphate, 20g / L of malonic acid, 4g / L of nickel sulfate and It is made of ionized water, the operating temperature is 50°C, the pH value is controlled at 2.4, and the passivation time is 80 seconds. The surface color of the metal zinc layer is bright black, and the surface has a uniform passivation film. The test result of the neutral salt spray test 96H is 10.

Embodiment 3

[0011] The formula is: chromium chloride is 25 / L, chromium nitrate is 5g / L, cobalt nitrate is 6g / L, sodium dihydrogen phosphate is 20g / L, malonic acid is 30g / L, nickel sulfate is 5g / L and It is made of ionized water, the operating temperature is 60°C, the pH value is controlled at 2.2, and the passivation time is 80 seconds. The surface color of the metal zinc layer is bright black, and the surface has a uniform passivation film. The test result of the neutral salt spray test 96H is 10.

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Abstract

The invention provides a preparation method of a trivalent chromium black passivator. The trivalent chromium black passivator is composed of chromium chloride, chromic nitrate, cobalt nitrate, sodium dihydrogen phosphate, nickel sulfate, malonic acid and deionized water. The black trivalent chromium passivator can obtain a black film with favorable binding force, and the white rust appearance time in the neutral salt fog experiment is longer than 96 hours. The passivation solution has the advantages of stable performance, low cost price and favorable properties.

Description

technical field [0001] The invention relates to a preparation method of a passivator used for the passivation treatment of metal zinc surfaces, in particular to a preparation method of a trivalent chromium black passivator. Background technique [0002] In recent years, with the rapid development of modern industry, more and more industries, such as electronics, instruments, optical instruments, automobile and motorcycle parts, daily hardware and architectural decoration, etc., have put forward more and more requirements for the black surface film layer. high demands. The black passivation of galvanized layer has the advantages of low price and good performance, so it has been widely used. Most of the existing black passivation processes contain hexavalent chromium. However, hexavalent chromium is toxic, and its application is gradually limited. Since trivalent chromium passivation has similar properties to hexavalent chromium passivation in many respects, its toxicity is...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C22/07
Inventor 张汝山
Owner TIANJIN DAGANG GALVANIZED FACTORY
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